Electronic vs digital signature
An electronic signature is a legal idea: a person showing they agree, by drawing, typing or clicking. A digital signature is a technical one: maths over a file that shows it hasn't changed since it was signed. A good e-signature process uses both.
By docuinked. Published 2026-11-08, updated 2026-11-08.
Side by side
| Electronic signature | Digital signature | |
|---|---|---|
| What it is | Any sound, symbol or process a person uses to sign, with intent | A cryptographic value computed over the file with a private key |
| What it looks like | A drawn or typed name, a click on "I agree" | Usually nothing visible; a reader shows a signature panel or banner |
| What it shows | That a person meant to agree | That the file is the same as when it was signed, and which key signed it |
| What it doesn't show | That the file is unchanged afterwards | That a particular person meant to agree |
| Examples | Signing in Preview or Markup, an e-signature link | A certificate signature in Acrobat, a PAdES seal |
Electronic signatures
In the US, the ESIGN Act and state UETA laws say a signature can't be refused just because it's electronic. The law cares about intent, not appearance. Your drawn signature in Preview counts, and so can a typed name, if you meant to sign.
The weakness is proof. A signature image on a PDF can be copied, and the PDF can be edited after signing. If someone later says "I never signed that", the image alone doesn't settle it. See is an electronic signature legal for how courts look at this.
Digital signatures
A digital signature uses a key pair. The signer's software hashes the file and signs the hash with a private key. Anyone with the matching public key can check that the file hasn't changed by a single byte. Inside PDFs, the standard for this is PAdES, which we explain in what is PAdES.
A digital signature says which key signed, not which human meant to agree. A certificate links the key to a name, and how much that's worth depends on who issued the certificate and how they checked identity.
You usually want both
The strong setup puts a person's electronic signature on the document, records each step around it (who got the link, when they opened it, when they signed), and then applies a digital signature to the finished file so any later change shows. That's how e-signature services work, docuinked included.
docuinked seals each completed PDF with a PAdES signature and an outside timestamp, and adds a certificate of completion and an audit trail. One honest limit: our seal certificate isn't on Adobe's trust list yet, so Acrobat names the signer as unknown, while its check that the file is unchanged still works. Anyone can check a file with our free PDF checker.
How to add a digital signature yourself
Acrobat Reader can apply a certificate-based signature if you have a digital ID; look for the option to sign with a certificate or digital ID in its signing tools. Most people never need to. If you're signing a form that someone else asked for, a normal electronic signature is what they expect. For the everyday steps, see how to sign a PDF.
Common questions
Is a digital signature more valid than an electronic one?
Not by default. In the US, both can satisfy a signature requirement. A digital signature adds proof that the file hasn't changed, which helps if the document is ever disputed.
Is a scanned handwritten signature an electronic signature?
Yes, if you put it there meaning to sign. It's an image like any other, so it carries the same weakness: it can be copied and the file edited around it.
Why does Acrobat show a blue banner on some signed PDFs?
That banner comes from a digital signature in the file. Acrobat is reporting whether the file is unchanged since signing and whether it trusts the certificate that signed it.
Do I need a certificate to sign a PDF electronically?
No. A certificate is only for digital signatures. Drawing or typing your signature in a free tool needs nothing extra.
Related
Try it in test mode
Free during the beta. Test keys send no email, so you can build the whole flow first.